There can be changes to a person's eyesight after a brain injury has occurred. This can include problems with the field of vision, the position of the eye and how the eye moves. There are different treatments and strategies to help reduce or adapt to vision related difficulties.

What can happen to eyesight after brain injury?

The visual system is large and complex. The picture travels from the eyeball to the occipital cortex at the back of the brain (see Figure 1). Information is received by the eyeball and then transferred in special nerves to the back of the brain where it is decoded into what we 'see'. The occipital lobe is the area of the brain where information processed by the eyes is decoded and information about what we see (colour, shape and distance) is understood.

Figure 1

Injury to any part of this pathway can lead to problems with eyes and vision (see Figure 2). Problems with eye positions (squint or strabismus, double vision), eye movements (jerky eyes, nystagmus, poor tracking), visual field defects and vision problems are common after a brain injury. Over time these visual difficulties tend to improve.

Symptoms

Double vision

Double vision (diplopia) is caused by an imbalance of the eye muscle movements. The two images, one from each eye, are not aligned properly and so the child sees this as a double image. A child may close or cover one eye to look at something or have difficulty with balance or judging depth. They may have difficulty reading and copying. The child may have a squint or turn of one of their eyes.

Visual field defect

Visual field defect (hemianopia) is due to an interruption of the visual pathways in the brain. The result is a loss of vision in one half of the visual field in each eye (see Figure 3). A child may not pay attention to one side, may bump into objects on one side of the body or only draw on one side of a page.

Poor visual acuity

Poor visual acuity is when you cannot see clearly. This is tested by using eye charts with letters or pictures. Special tests are available to test those children who cannot name pictures or read letters.

Squint

Squint (strabismus) is when the eyes are not in line with each other. Children may tilt or turn their head to try and line the eyes up because the eyes cannot correct the position themselves.

Treatment

Eyeball problems

If the problem with vision is because of an eyeball problem, glasses can sometimes help. However, glasses are not usually helpful after a brain injury. Ways to compensate for the problem are needed while the child's eyes and vision recover.

Double vision

Patching one eye can relieve double vision. It is important to swap eyes with the patch so that one eye does not become weak from lack of use. Patching can also help strengthen the muscles that cause a squint. To help a squint, the eye with better vision is patched making the weaker eye work and straighten its position.

Poor visual acuity

• reduce the amount of information presented on a worksheet
• enlarge pictures and writing
• have well contrasted pictures (i.e. strong black and white) in books
• use felt tipped pens for drawing and writing
• make sure the child has good lighting and good seating for school and homework
• use a slope board on desks if the child has difficulty looking down

If a child has a very severe vision impairment, Vision Australia should be involved. They provide a comprehensive service for home and school to help children with vision difficulties.

Visual field defects

Teaching children to look or scan left and right will help them be aware of people or objects in their 'blind spot'.

When to see a doctor?

Your GP, paediatrician or neurologist can assess your child's eyes and vision, and they may refer your child to see an ophthalmologist and an orthoptist.  

An ophthalmologist is a doctor who specialises in disorders of the eye. An orthoptist is a person who specialises in assessment of eyes and vision. Most children who have difficulties with eyes and vision after a brain injury see both an ophthalmologist and an orthoptist.

Key points to remember

• Problems with eye movements and positions, visual field defects and vision problems are common after a brain injury.
• Over time, the visual difficulties tend to improve.
• A GP, paediatrician or neurologist can assess your child's eyes and vision, and can refer your child to see an ophthalmologist and/or an orthoptist.

For more information

• The Royal Children's Hospital
  Victorian Paediatric Rehabilitation Service
  T: (03) 9345 9300
  E: rehab.service@rch.org.au
  
• The Children's Hospital at Westmead Brain injury Service
  
• Kids Health Info series of fact sheets under 'Brain injury'

Developed by The Royal Children's Hospital Paediatric Rehabilitation Service. We acknowledge the input of RCH consumers and carers.

Reviewed August 2020.

Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.